calculating cell delays by using non linear delay models...

hello everyone...

can anybody explain the process of calculating the cell delays by using non-linear delay models and composite current source techniques....

thanQ...!!!

In non-linear delay model, the input slew is determined using the driver and load at the input. Using this information, entries in the .lib for the cell which is being driven, the delay is calculated using linear interpolation. Example if you have input slew of 50ps and the load on the gate is 100ff, the primetime tool will read the .lib for these two sets in the 7x7 database for the delay. If these exact numbers are not available the tool will interpolate between the nearest value available in the .lib.

Current composite : In this case the dynamic current information of the driver is present in the .lib. using that current source and load which is based on receiver models( two sets of capacitance one lower than vdd/2 and one higher) the actual transition time is calculated thereby the delay through the cell.

Current composte modelling is accurate and it is required for newer technologies. If you have more questions, please email me....it is kind of difficult to explain in an email ;-)

G.Satheesh Kumar said:

hello everyone...

can anybody explain the process of calculating the cell delays by using non-linear delay models and composite current source techniques....

thanQ...!!!

Click to expand...

tanQ @artmalik.... but can u explain in some more detailed manner..!!!